AS200887 - VELCOM-IT Velcom SrlPARFC 4890 ✓RPKI ✓ 1/1ASPA -

AS overview

Test target: 2a13:1580::1 · static prefix probe · address space: PA · prefixes announced: 1

prefix(es): 2a13:1580::/29

Random-IP probe (yarrp) into the AS' prefixes

We probed 15 arbitrary IPv6 address(es) inside AS200887's announced prefix(es). No router inside the prefix responded. The deepest visible hop was fd13:1580::2 at hop 12 - that router does not answer ICMPv6 Echo. This is not in AS200887's announced prefix; operationally it's the AS-edge / peering interface (often on an IXP peering address or an upstream's /127 link). The traceroute boundary is the AS edge: ICMPv6 Time-Exceeded responses from anything inside this AS are filtered.

ICMPv6 Type 2 (Packet Too Big) acceptance - active test

Vantage points disagree about Type 2 acceptance - transit ASes on one path may be filtering Type 2 even though the destination's stack accepts it on another path:

• NL host (go6lab): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
• ITA host (Karsolink): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (active test)
• SLO host (6connect): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)

Why they disagree - different probe methods: These vantages picked different probe methods, so their verdicts are not directly comparable. The active test tries methods in order (icmp6-echo → dns-tcp → tls → http) and stops at the first that produces a definitive verdict; if the chosen method differs, the underlying evidence differs too. Most often this is because the path PMTU on one vantage is below 1500 B, so the natural Echo Reply is already fragmented and the icmp6-echo method falls through to a TCP-based one. This is largely a measurement artifact, not a destination-behaviour difference.

sudo tcpdump -i any -n -e 'icmp6 and ip6[40] = 2 and (src host 2607:fae0:a000::42 or src host 2a00:8642:42::75 or src host 2a12:d8c0:105a:9001::a154)'

sudo ip6tables -L INPUT -nv | grep -iE 'icmpv6|packet-too-big'
sudo nft list ruleset 2>/dev/null | grep -A1 'icmpv6'

sudo sysctl net.ipv6.conf.all.accept_redirects net.ipv4.ip_no_pmtu_disc net.ipv6.route.mtu_expires

sudo tcpdump -i any -n -e 'icmp6 and ip6[40] = 2 and (src host 2607:fae0:a000::42 or src host 2a00:8642:42::75 or src host 2a12:d8c0:105a:9001::a154)'

From NL host (go6lab)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.027ms pmtu 1500
 1:  2a00:8642:42::3                                       2.133ms 
 1:  2a00:8642:42::3                                       2.029ms 
 2:  gw.friends.steffann.nl                                2.961ms 
 3:  speed-ix.fibertelecom.it                              4.130ms 
 4:  2a03:b020::254                                       27.707ms asymm  7 
 5:  2a03:b020:1:5c::b                                    27.328ms asymm  8 
 6:  2a13:1580::1                                         29.915ms reached
     Resume: pmtu 1500 hops 6 back 9 

From ITA host (Karsolink)   openRFC 4890 ✗

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.053ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.862ms 
 2:  2a12:d8c0:109f:121::a1                                0.709ms 
 3:  no reply
 4:  2a03:b020:1:51::a                                    10.758ms 
 5:  2a03:b020::254                                       19.064ms asymm  7 
 6:  2a03:b020:1:5c::b                                    19.113ms asymm  8 
 7:  2a13:1580::1                                         21.623ms reached
     Resume: pmtu 1500 hops 7 back 9 

From SLO host (6connect)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.029ms pmtu 1500
 1:  fw1-lju.6connect.com                                  0.466ms 
 1:  fw1-lju.6connect.com                                  0.476ms 
 2:  no reply
 3:  2a03:a100:0:201:1::1                                  1.018ms 
 4:  e0-1.core1.lju1.he.net                                2.257ms 
 5:  100ge0-0-0-5.core1.vie1.he.net                        8.684ms 
 6:  e0-35.core2.muc1.he.net                              12.254ms 
 7:  ipv6.de-cix.muc.as41327.fibertelecom.com             17.680ms asymm 10 
 8:  2a03:b020::254                                       27.493ms asymm  9 
 9:  2a03:b020:1:5c::b                                    27.639ms asymm 10 
10:  2a13:1580::1                                         30.144ms reached
     Resume: pmtu 1500 hops 10 back 11